1. Academic Validation
  2. Electroacupuncture Exerts Analgesic Effects by Restoring Hyperactivity via Cannabinoid Type 1 Receptors in the Anterior Cingulate Cortex in Chronic Inflammatory Pain

Electroacupuncture Exerts Analgesic Effects by Restoring Hyperactivity via Cannabinoid Type 1 Receptors in the Anterior Cingulate Cortex in Chronic Inflammatory Pain

  • Mol Neurobiol. 2023 Nov 13. doi: 10.1007/s12035-023-03760-7.
Junshang Wu 1 Libo Hua 2 Wenhao Liu 2 Xiaoyun Yang 2 3 Xiaorong Tang 2 Si Yuan 2 Sheng Zhou 2 Qiuping Ye 4 Shuai Cui 5 Zhennan Wu 2 Lanfeng Lai 2 Chunzhi Tang 2 Lin Wang 2 Wei Yi 2 Lulu Yao 6 Nenggui Xu 7
Affiliations

Affiliations

  • 1 Department of Acupuncture and Moxibustion, the Second Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China.
  • 2 South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China.
  • 3 Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China.
  • 4 Department of Rehabilitation MedicineThe Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
  • 5 Acupuncture and Meridian Research Institute, Anhui Academy of Chinese Medicine, Anhui, China.
  • 6 South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China. yaolulu@gzucm.edu.cn.
  • 7 South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China. ngxu8018@163.com.
Abstract

As one of the commonly used therapies for pain-related diseases in clinical practice, electroacupuncture (EA) has been proven to be effective. In chronic pain, neurons in the anterior cingulate cortex (ACC) have been reported to be hyperactive, while the mechanism by which cannabinoid type 1 receptors (CB1Rs) in the ACC are involved in EA-mediated analgesic mechanisms remains to be elucidated. In this study, we investigated the potential central mechanism of EA analgesia. A combination of techniques was used to detect the expression and function of CB1R, including quantitative Real-Time PCR (q-PCR), western blot (WB), immunofluorescence (IF), enzyme-linked immunosorbent assay (ELISA), and in vivo multichannel optical fibre recording, and neuronal activity was examined by in vivo two-photon imaging and in vivo electrophysiological recording. We found that the hyperactivity of pyramidal neurons in the ACC during chronic inflammatory pain is associated with impairment of the endocannabinoid system. EA at the Zusanli acupoint (ST36) can reduce the hyperactivity of pyramidal neurons and exert analgesic effects by increasing the endocannabinoid ligands anandamide (AEA), 2-arachidonoylglycerol (2-AG) and CB1R. More importantly, CB1R in the ACC is one of the necessary conditions for the EA-mediated analgesia effect, which may be related to the negative regulation of the N-methyl-D-aspartate receptor (NMDAR) by the activation of CB1R downregulating NR1 subunits of NMDAR (NR1) via histidine triad nucleotide-binding protein 1 (HINT1). Our study suggested that the endocannabinoid system in the ACC plays an important role in acupuncture analgesia and provides evidence for a central mechanism of EA-mediated analgesia.

Keywords

Analgesia; Anterior cingulate cortex; Cannabinoid type 1 receptor; Electroacupuncture; Inflammatory pain.

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